Study to focus on how chemicals affect Chicago fish

Are estrogen and similar chemicals in Chicago waterways thinning fish populations?

The Metropolitan Water Reclamation District of Greater Chicago is opening a new chapter in its efforts to find out.

The district board commissioners is eyeing a study - at just over $328, 500 - to assess how chemicals known as endocrine disruptors affect fish reproduction in the Chicago waterways.

Commissioners will vote on the award tomorrow at the board’s last regular meeting of the year.

The meeting is scheduled for 10 a.m. at 100 E. Erie.

The MWRD is collaborating with St. Cloud State University in Minnesota on the three-year study, which will commence in 2009.

Heiko Schoenfuss, professor in the biological sciences department and director of the aquatic toxicology laboratory at St. Cloud, will be the principle investigator for the study.

“Endocrine disruptors are found in many places where humans have altered the aquatic environment, “says Schoenfuss, who adds that fish are believed to be very susceptible their effects.

“We’ve found that a female hormone, like estrogen, can commonly cause a male fish to become feminized.”

Endocrine disruptors are naturally occurring and synthetic compounds that can alter the endocrine system’s ability to regulate growth, development and reproduction through the release of hormones.

Common sources of these chemicals include plastics, detergents, pesticides and pharmaceuticals.Schoenfuss says the St. Cloud team brings a lot of experience in working with large waterways.

In 2006 Schoenfuss headed a study intended to gauge the presence of endocrine disruptors in the first 900 miles of the Mississippi River, from its origin in Lake Itasca in Minnesota.

He characterizes the results as “very complex.”

The presence of the chemical compound decreased along less populated stretches, indicating that the river could “rebound,” he says.

“Once we got into the more urbanized corridor around the Twin Cities, though, we saw a consistent estrogenic signature that was both in the fish and the water and sediment chemistry,” says Schoenfuss.

The Chicago area study, Schoenfuss says, is key to helping scientists figure out specifically how fish reproduction is being impacted by these contaminants.

“The Mississippi River is such a large, open-ended system,” says Schoenfuss. “The Chicago River system is much more constrained in its input and outflows; we should be able to address that question much better there.”

Jill Horist, spokesperson for the MWRD, says the district collaborated with the U.S. Environmental Protection Agency on similar studies in 2007 and 2008.

Those studies revealed no deformities in fish either up or downstream from the Stickney or Calumet plants, says Horist.

“We continue to monitor this issue very closely,” says Horist. “This study will be looking at different parts of the river and different varieties of fish.”

In July, the MWRD commissioned a study to determine how often Chicagoans are flushing medications down the toilet. Some of these medications could contain endocrine disruptors, say district officials, and might end up in the river.

Study results are being used to shape a public information campaign to promote awareness of proper disposal methods, says Horist.

Some studies have linked endocrine disruptors to reproductive cancers and decreased sperm count in humans, but the research is inconclusive.

The effects of these compounds on humans are “still an area of very active discussion for scientists,” says Schoenfuss.

At tomorrow’s meeting, board members may also vote on final amendments to the MWRD 2009 budget, which, as adopted by commissioners on Dec. 11 stands at $1.6 billion.

Jennifer Slosar is a Chicago-based freelance journalist. She covers environmental issues for the Daily News